senses part 2

Question 1

• inner layer of the eyeball
• lines the posterior 3/4 of the eyeball
• is the beginning of the visual pathway
  by converting light to nerve impulses
• contains layers of neurons w/c are of 3
  main types

Answer 1

RETINA

Question 2

• are specialized cells that begin the
  process by which light rays are
  converted to nerve impulses
• has 2 types

Answer 2

Photoreceptors

Question 3

• most abundant photoreceptor (120
  million in each retina)
• are more sensitive to light
• permit vision in dim light
• do not permit color vision; only
  permit seeing black, white, & all
  shades of gray in dim light

Answer 3

Rods

Question 4

• 6 million in each retina
• stimulated by brighter lights
• produce color vision w/c results
  from the stimulation of various
  combinations of 3 types of cones:

red cones
green cones
blue cones

Answer 4

Cones

Question 5

• receive nerve impulses from
  photoreceptors & transmit them to
  ganglion cells

Answer 5

• receive nerve impulses from
  photoreceptors & transmit them to
  ganglion cells